Mom: Fred, there were two chocolate cakes in the larder yesterday, and now there's only one.
Why?
Fred: I don't know. It must have been so dark I didn't see the other
one.

I went to see my doctor to see if he could help me give up smoking.
What did he say?
He suggested that every time I felt like a smoke I should reach for a bar of chocolate.
Did that do any good?
No - I can't get the chocolate to light.